TermMorphologyMeaning
قَسْوَةٌRoot-related nounHardness
قَاسَىForm III pastEndured/suffered
مُقَاسَاةٌForm III verbal nounEnduring suffering
The terms share a root-related semantic field, but the Form III word carries its own lexical sense. That is the point of ibtidāʾ in this chapter.